The Experts below are selected from a list of 1860 Experts worldwide ranked by ideXlab platform
Frederik J Hilgen - One of the best experts on this subject based on the ideXlab platform.
-
Improved astronomical age constraints for the middle Miocene climate transition based on high‐resolution stable isotope records from the central Mediterranean Maltese Islands
Paleoceanography, 2011Co-Authors: Anja A. Mourik, Frederik J Hilgen, Hemmo A. Abels, Agata Di Stefano, Willem-jan ZachariasseAbstract:[1] Marine outcrops of the Globigerina Limestone and Blue Clay formations on the Maltese Islands in the central Mediterranean document the middle Miocene climate transition between ∼15 and 13.5 million years ago. Here high-resolution benthic and planktic oxygen isotope records have been constructed for this enigmatic interval in Cenozoic climate evolution. Detailed biostratigraphic correlations to the astronomically tuned La Vedova section in northern Italy allow revision of the tuning of the Blue Clay Formation, constraining the age of the sediments directly above the formation boundary and hence the Mi-3b oxygen isotope event and Serravallian Global Stratotype Section and Point (GSSP). Biostratigraphic age control and cyclic patterns in the benthic carbon isotope record further lead to an astronomically-tuned age model for the Upper Member of the Globigerina Limestone Formation. Start of sedimentation of the Upper Globigerina Limestone is dated at ∼14.95 Ma, and the oldest Blue Clay sediments have a revised astronomical age of 13.76 ± 0.02 Ma. Our data indicates that a hiatus between 13.95 and 13.76 Ma cannot be excluded and could have implications for the Serravallian GSSP currently defined in this section. The global middle Miocene cooling is reflected in the benthic oxygen isotope record, showing a ∼0.6‰ increase (Mi-3b) between ∼13.95 and 13.76 Ma. A divergence between the planktic and benthic oxygen and carbon isotope records after 13.76 Ma could point to a decrease in ventilation, possibly related to increased fresh water influx after the climate transition.
-
The Global Stratotype Section and Point (GSSP) of the Serravallian Stage (Middle Miocene)
Episodes, 2009Co-Authors: Frederik J Hilgen, Wout Krijgsman, Silvia Maria Iaccarino, Rodolfo Sprovieri, Hemmo A. Abels, Isabella Raffi, E. Turco, Willem-jan ZachariasseAbstract:The Global Stratotype Section and Point (GSSP) for the Base of the Serravallian Stage (Middle Miocene) is defined in the Ras il Pellegrin section located in the coastal cliffs along the Fomm Ir-Rih Bay on the west coast of Malta (35°54'50"N, 14°20'10"E). The GSSP is at the base of the Blue Clay Formation (i.e., top of the transitional bed of the uppermost Globigerina Limestone). This boundary between the Langhian and Serravallian stages coincides with the end of the major Mi-3b global cooling step in the oxygen isotopes and reflects a major increase in Antarctic ice volume, marking the end of the Middle Miocene climate transition and the Earth's transformation into an "Icehouse" climate state. The associated major glacio-eustatic sea-level drop corresponds with sequence boundary Ser1 of Hardenbol et al. (1998) and supposedly with the TB2.5 sequence boundary of Haq et al (1987). This event is slightly older than the last common and/or continuous occurrence of the calcareous nannofossil Sphenolithus heteromorphus, previously considered as guiding criterion for the boundary, and is projected to fall within the younger half of Chron C5ACn. The GSSP level is in full agreement with the definitions of the Langhian and Serravallian in their respective historical stratotype sections in northern Italy and has an astronomical age of 13.82 Ma.
-
Radioisotopic dating of the Tortonian Global Stratotype Section and Point: implications for intercalibration of 40Ar/39Ar and astronomical dating methods
Terra Nova, 2005Co-Authors: Klaudia F. Kuiper, Jan Wijbrans, Frederik J HilgenAbstract:In this paper we present new 40 Ar/ 39 Ar data of volcanic ash layers intercalated in the astronomically dated sections of Monte dei Corvi and Monte Gibliscemi (Italy) to obtain better radioisotopic time constraints on the Serravallian/Tortonian boundary and to confirm the intercalibration of radioisotopic and astronomical time proposed by Kuiper et al. [2004; Fish Canyon Tuff (FCT)-sanidine at 28.21 ± 0.03 Ma]. The latter intercalibration is supported by astronomically calibrated FCT sanidine ages for two ash layers at Monte Gibliscemi (GiF-1: 28.28 ± 0.04; GiD-3: 28.16 ± 0.04 Ma; ±1 SE). As a consequence, our results support the astronomically calibrated age of 11.608 Ma for the Tortonian Global Stratotype Section and Point and, hence, the tuning of the Serravallian/ Tortonian boundary interval. The Ancona and Respighi levels at Monte dei Corvi give a more diffuse picture, possibly because of contamination with detrital or xenocrystic material and the inferior quality of biotite for intercalibration
-
integrated stratigraphy and astronomical tuning of the Serravallian and lower tortonian at monte dei corvi middle upper miocene northern italy
Palaeogeography Palaeoclimatology Palaeoecology, 2003Co-Authors: Frederik J Hilgen, Wout Krijgsman, Isabella Raffi, Abdul H Aziz, E. TurcoAbstract:An integrated stratigraphy (calcareous plankton biostratigraphy, magnetostratigraphy and cyclostratigraphy) is presented for the Serravallian and lower Tortonian part (Middle^Upper Miocene) of the Monte dei Corvi section located in northern Italy.The detailed biostratigraphic analysis showed that both the Discoaster kugleri acme and the first influx of Neogloboquadrina acostaensis are recorded at Monte dei Corvi; these events, which passed unobserved in previous studies, play an important role in delineating the Serravallian^Tortonian boundary.Thermal and alternating field demagnetization revealed a characteristic low-temperature component marked by dual polarities.The resultant magnetostratigraphy for the upper part of the section can be unambiguously calibrated to the GPTS ranging from C5n.2n up to C4r.2r. Unfortunately, the lower part of the section, including the Serravallian^Tortonian boundary interval, did not produce a reliable magnetostratigraphy despite the fact that some short reversed intervals and a single normal interval are recorded.Using sedimentary cycle patterns in combination with the calcareous plankton biostratigraphy the section can be correlated cyclostratigraphically in detail to the partially overlapping and previously tuned section of Monte Gibliscemi on Sicily.The Monte dei Corvi section is dated astronomically by calibrating the basic small-scale sedimentary cycles to the precession and 65‡N lat.summer insolation time series of the La93 solution following an initial tuning of larger-scale cycles to eccentricity.An almost perfect fit is found between the cycle patterns and intricate details, especially precession^obliquity interference, in the insolation target between 8.5 and 10 Ma. The tuning to precession remains robust for most intervals back to the base of the section dated at 13.4 Ma and shows that the section is continuous apart from a possible short hiatus in the Tortonian. It provides accurate astronomical ages for all sedimentary cycles, calcareous plankton events, polarity reversals and ash layers and marks a significant improvement of the recently proposed astronomical calibrations of the Monte dei Corvi section and of parallel sections in the Mediterranean.Astronomical ages for the Ancona and Respighi ashbeds are significantly older than previously reported 40 Ar/ 39 Ar biotite ages, even if the revised older age for the FCT-san dating standard of 28.02 Ma is applied. The astronomical dating of the magnetic reversals in the Monte dei Corvi section results in the completion of the astronomical polarity time scale for the last 13 Myr.The Monte dei Corvi section has recently been proposed as the stratotype section for the Serravallian^Tortonian boundary despite the moderate to
-
Integrated stratigraphy and astronomical tuning of the Serravallian and lower Tortonian at Monte dei Corvi (Middle–Upper Miocene, northern Italy)
Palaeogeography Palaeoclimatology Palaeoecology, 2003Co-Authors: Frederik J Hilgen, Wout Krijgsman, Isabella Raffi, H. Abdul Aziz, E. TurcoAbstract:An integrated stratigraphy (calcareous plankton biostratigraphy, magnetostratigraphy and cyclostratigraphy) is presented for the Serravallian and lower Tortonian part (Middle^Upper Miocene) of the Monte dei Corvi section located in northern Italy.The detailed biostratigraphic analysis showed that both the Discoaster kugleri acme and the first influx of Neogloboquadrina acostaensis are recorded at Monte dei Corvi; these events, which passed unobserved in previous studies, play an important role in delineating the Serravallian^Tortonian boundary.Thermal and alternating field demagnetization revealed a characteristic low-temperature component marked by dual polarities.The resultant magnetostratigraphy for the upper part of the section can be unambiguously calibrated to the GPTS ranging from C5n.2n up to C4r.2r. Unfortunately, the lower part of the section, including the Serravallian^Tortonian boundary interval, did not produce a reliable magnetostratigraphy despite the fact that some short reversed intervals and a single normal interval are recorded.Using sedimentary cycle patterns in combination with the calcareous plankton biostratigraphy the section can be correlated cyclostratigraphically in detail to the partially overlapping and previously tuned section of Monte Gibliscemi on Sicily.The Monte dei Corvi section is dated astronomically by calibrating the basic small-scale sedimentary cycles to the precession and 65‡N lat.summer insolation time series of the La93 solution following an initial tuning of larger-scale cycles to eccentricity.An almost perfect fit is found between the cycle patterns and intricate details, especially precession^obliquity interference, in the insolation target between 8.5 and 10 Ma. The tuning to precession remains robust for most intervals back to the base of the section dated at 13.4 Ma and shows that the section is continuous apart from a possible short hiatus in the Tortonian. It provides accurate astronomical ages for all sedimentary cycles, calcareous plankton events, polarity reversals and ash layers and marks a significant improvement of the recently proposed astronomical calibrations of the Monte dei Corvi section and of parallel sections in the Mediterranean.Astronomical ages for the Ancona and Respighi ashbeds are significantly older than previously reported 40 Ar/ 39 Ar biotite ages, even if the revised older age for the FCT-san dating standard of 28.02 Ma is applied. The astronomical dating of the magnetic reversals in the Monte dei Corvi section results in the completion of the astronomical polarity time scale for the last 13 Myr.The Monte dei Corvi section has recently been proposed as the stratotype section for the Serravallian^Tortonian boundary despite the moderate to
Jean-luc Auxietre - One of the best experts on this subject based on the ideXlab platform.
-
Tectonic and stratigraphic evolution of the Western Alboran Sea Basin in the last 25 Myrs
Tectonophysics, 2016Co-Authors: Damien Do Couto, Christian Gorini, Laurent Jolivet, Noëmie Lebret, Romain Augier, Charles Gumiaux, Elia D 'acremont, Abdellah Ammar, Haddou Jabour, Jean-luc AuxietreAbstract:The Western Alboran Basin (WAB) formation has always been the subject of debate and considered either as a back-arc or a forearc basin. Stratigraphic analyses of high-resolution 2D seismic profiles mostly located offshore Morocco, enabled us to clarify the tectonic and stratigraphic history of the WAB. The thick pre-rift sequence located beneath the Miocene basin is interpreted as the topmost Malaguide/Ghomaride complex composing the Alboran domain. The structural position of this unit compared with the HP–LT exhumed Alpujarride/Sebtide metamorphic basement, leads us to link the Early Miocene subsidence of the basin with an extensional detachment. Above the Early Miocene, a thick Serravallian sequence marked by siliciclastic deposits is nearly devoid of extensional structures. Its overall landward to basinward onlap geometry indicates that the WAB has behaved as a sag basin during most of its evolution from the Serravallian to the late Tortonian. Tectonic reconstructions in map view and in cross section further suggest that the basin has always represented a strongly subsiding topographic low without internal deformation that migrated westward together with the retreating slab. We propose that the subsidence of the WAB was controlled by the pull of the dipping subducting lithosphere hence explaining the considerable thickness (10 km) of the mostly undeformed sedimentary infill.
-
Tectonic and stratigraphic evolution of the Western Alboran Sea Basin in the last 25 Myrs
Tectonophysics, 2016Co-Authors: Damien Do Couto, Christian Gorini, Laurent Jolivet, Noëmie Lebret, Romain Augier, Charles Gumiaux, Elia D 'acremont, Abdellah Ammar, Haddou Jabour, Jean-luc AuxietreAbstract:International audienceThe Western Alboran Basin (WAB) formation has always been the subject of debate and considered either as a back-arc or a forearc basin. Stratigraphic analyses of high-resolution 2D seismic profiles mostly located offshore Morocco, enabled us to clarify the tectonic and stratigraphic history of the WAB. The thick pre-rift sequence located beneath the Miocene basin is interpreted as the topmost Malaguide/Ghomaride complex composing the Alboran domain. The structural position of this unit compared with the HP–LT exhumed Alpujarride/Sebtide metamorphic basement, leads us to link the Early Miocene subsidence of the basin with an extensional detachment. Above the Early Miocene, a thick Serravallian sequence marked by siliciclastic deposits is nearly devoid of extensional structures. Its overall landward to basinward onlap geometry indicates that the WAB has behaved as a sag basin during most of its evolution from the Serravallian to the late Tortonian. Tectonic reconstructions in map view and in cross section further suggest that the basin has always represented a strongly subsiding topographic low without internal deformation that migrated westward together with the retreating slab. We propose that the subsidence of the WAB was controlled by the pull of the dipping subducting lithosphere hence explaining the considerable thickness (10 km) of the mostly undeformed sedimentary infill
E. Turco - One of the best experts on this subject based on the ideXlab platform.
-
The Global Stratotype Section and Point (GSSP) of the Serravallian Stage (Middle Miocene)
Episodes, 2009Co-Authors: Frederik J Hilgen, Wout Krijgsman, Silvia Maria Iaccarino, Rodolfo Sprovieri, Hemmo A. Abels, Isabella Raffi, E. Turco, Willem-jan ZachariasseAbstract:The Global Stratotype Section and Point (GSSP) for the Base of the Serravallian Stage (Middle Miocene) is defined in the Ras il Pellegrin section located in the coastal cliffs along the Fomm Ir-Rih Bay on the west coast of Malta (35°54'50"N, 14°20'10"E). The GSSP is at the base of the Blue Clay Formation (i.e., top of the transitional bed of the uppermost Globigerina Limestone). This boundary between the Langhian and Serravallian stages coincides with the end of the major Mi-3b global cooling step in the oxygen isotopes and reflects a major increase in Antarctic ice volume, marking the end of the Middle Miocene climate transition and the Earth's transformation into an "Icehouse" climate state. The associated major glacio-eustatic sea-level drop corresponds with sequence boundary Ser1 of Hardenbol et al. (1998) and supposedly with the TB2.5 sequence boundary of Haq et al (1987). This event is slightly older than the last common and/or continuous occurrence of the calcareous nannofossil Sphenolithus heteromorphus, previously considered as guiding criterion for the boundary, and is projected to fall within the younger half of Chron C5ACn. The GSSP level is in full agreement with the definitions of the Langhian and Serravallian in their respective historical stratotype sections in northern Italy and has an astronomical age of 13.82 Ma.
-
integrated stratigraphy and astronomical tuning of the Serravallian and lower tortonian at monte dei corvi middle upper miocene northern italy
Palaeogeography Palaeoclimatology Palaeoecology, 2003Co-Authors: Frederik J Hilgen, Wout Krijgsman, Isabella Raffi, Abdul H Aziz, E. TurcoAbstract:An integrated stratigraphy (calcareous plankton biostratigraphy, magnetostratigraphy and cyclostratigraphy) is presented for the Serravallian and lower Tortonian part (Middle^Upper Miocene) of the Monte dei Corvi section located in northern Italy.The detailed biostratigraphic analysis showed that both the Discoaster kugleri acme and the first influx of Neogloboquadrina acostaensis are recorded at Monte dei Corvi; these events, which passed unobserved in previous studies, play an important role in delineating the Serravallian^Tortonian boundary.Thermal and alternating field demagnetization revealed a characteristic low-temperature component marked by dual polarities.The resultant magnetostratigraphy for the upper part of the section can be unambiguously calibrated to the GPTS ranging from C5n.2n up to C4r.2r. Unfortunately, the lower part of the section, including the Serravallian^Tortonian boundary interval, did not produce a reliable magnetostratigraphy despite the fact that some short reversed intervals and a single normal interval are recorded.Using sedimentary cycle patterns in combination with the calcareous plankton biostratigraphy the section can be correlated cyclostratigraphically in detail to the partially overlapping and previously tuned section of Monte Gibliscemi on Sicily.The Monte dei Corvi section is dated astronomically by calibrating the basic small-scale sedimentary cycles to the precession and 65‡N lat.summer insolation time series of the La93 solution following an initial tuning of larger-scale cycles to eccentricity.An almost perfect fit is found between the cycle patterns and intricate details, especially precession^obliquity interference, in the insolation target between 8.5 and 10 Ma. The tuning to precession remains robust for most intervals back to the base of the section dated at 13.4 Ma and shows that the section is continuous apart from a possible short hiatus in the Tortonian. It provides accurate astronomical ages for all sedimentary cycles, calcareous plankton events, polarity reversals and ash layers and marks a significant improvement of the recently proposed astronomical calibrations of the Monte dei Corvi section and of parallel sections in the Mediterranean.Astronomical ages for the Ancona and Respighi ashbeds are significantly older than previously reported 40 Ar/ 39 Ar biotite ages, even if the revised older age for the FCT-san dating standard of 28.02 Ma is applied. The astronomical dating of the magnetic reversals in the Monte dei Corvi section results in the completion of the astronomical polarity time scale for the last 13 Myr.The Monte dei Corvi section has recently been proposed as the stratotype section for the Serravallian^Tortonian boundary despite the moderate to
-
Integrated stratigraphy and astronomical tuning of the Serravallian and lower Tortonian at Monte dei Corvi (Middle–Upper Miocene, northern Italy)
Palaeogeography Palaeoclimatology Palaeoecology, 2003Co-Authors: Frederik J Hilgen, Wout Krijgsman, Isabella Raffi, H. Abdul Aziz, E. TurcoAbstract:An integrated stratigraphy (calcareous plankton biostratigraphy, magnetostratigraphy and cyclostratigraphy) is presented for the Serravallian and lower Tortonian part (Middle^Upper Miocene) of the Monte dei Corvi section located in northern Italy.The detailed biostratigraphic analysis showed that both the Discoaster kugleri acme and the first influx of Neogloboquadrina acostaensis are recorded at Monte dei Corvi; these events, which passed unobserved in previous studies, play an important role in delineating the Serravallian^Tortonian boundary.Thermal and alternating field demagnetization revealed a characteristic low-temperature component marked by dual polarities.The resultant magnetostratigraphy for the upper part of the section can be unambiguously calibrated to the GPTS ranging from C5n.2n up to C4r.2r. Unfortunately, the lower part of the section, including the Serravallian^Tortonian boundary interval, did not produce a reliable magnetostratigraphy despite the fact that some short reversed intervals and a single normal interval are recorded.Using sedimentary cycle patterns in combination with the calcareous plankton biostratigraphy the section can be correlated cyclostratigraphically in detail to the partially overlapping and previously tuned section of Monte Gibliscemi on Sicily.The Monte dei Corvi section is dated astronomically by calibrating the basic small-scale sedimentary cycles to the precession and 65‡N lat.summer insolation time series of the La93 solution following an initial tuning of larger-scale cycles to eccentricity.An almost perfect fit is found between the cycle patterns and intricate details, especially precession^obliquity interference, in the insolation target between 8.5 and 10 Ma. The tuning to precession remains robust for most intervals back to the base of the section dated at 13.4 Ma and shows that the section is continuous apart from a possible short hiatus in the Tortonian. It provides accurate astronomical ages for all sedimentary cycles, calcareous plankton events, polarity reversals and ash layers and marks a significant improvement of the recently proposed astronomical calibrations of the Monte dei Corvi section and of parallel sections in the Mediterranean.Astronomical ages for the Ancona and Respighi ashbeds are significantly older than previously reported 40 Ar/ 39 Ar biotite ages, even if the revised older age for the FCT-san dating standard of 28.02 Ma is applied. The astronomical dating of the magnetic reversals in the Monte dei Corvi section results in the completion of the astronomical polarity time scale for the last 13 Myr.The Monte dei Corvi section has recently been proposed as the stratotype section for the Serravallian^Tortonian boundary despite the moderate to
Wout Krijgsman - One of the best experts on this subject based on the ideXlab platform.
-
Integrated bio-magnetostratigraphy of the Badenian reference section Ugljevik in southern Pannonian Basin - implications for the Paratethys history (middle Miocene, Central Europe)
Global and Planetary Change, 2019Co-Authors: Oleg Mandic, Stjepan Ćorić, Patrick Grunert, Karin Sant, Mădălina Elena Kallanxhi, Dörte Theobalt, Arjan De Leeuw, Wout KrijgsmanAbstract:Abstract The Central Paratethys was a large-scale Oligo-Miocene epicontinental sea located in Central and Eastern Europe. It was separated from the Mediterranean by the Alpine orogenic belt. The Paratethys progressively flooded the Pannonian back-arc basin that formed during the early to middle Miocene. Along the southern margin of the basin, the maximum extension of the Paratethys onto the flanks of the Dinarides Mountains occurred during the middle Miocene (Badenian). We have studied the most complete middle Miocene (Badenian-Sarmatian) Paratethys section located at this southern margin. It comprises a >1.5 Myr long, continuous marine depositional sequence, which is highly relevant for our understanding of the interplay between global climatic and regional geodynamic perturbations in this semi-isolated epicontinental basin. The investigated record is particularly important to assess the impact of the Middle Miocene Climate Transition, the Langhian-Serravallian glacial Mi-3b event, the syn-rift climax of the Pannonian Basin and the Badenian Salinity Crisis. Moreover, we present the first high resolution age model for the regional Badenian stage based on integrated biomagnetostratigraphy. According to our age model, the marine flooding reached the area at ~14.15 Ma, during the regional Badenian stage. Open marine conditions persisted until ~12.6 Ma when the extinction of the fully marine fauna marks the beginning of the regional Sarmatian stage. Sea-level fluctuations are reflected in the section by four transgressive regressive cycles coinciding roughly with 400-kyr-eccentricity periods. The largest sea-level fall occurred after the first cycle and corresponds to the end of the Middle Miocene Climate Transition marked by glacial event Mi-3b. Elsewhere in the Pannonian Basin, this marked drop in base-level triggered deposition of evaporites during the Badenian Salinity Crisis. At Ugljevik however, there are no evaporites and the short-term Mi-3b regression was followed by a transgression and re-establishment of deeper marine conditions at 13.76 Ma, i.e. during the earliest Serravallian. Diversified planktonic and benthic assemblages suggest fully marine conditions with a persistent connection to the Mediterranean at this time. Such conditions prevailed until the mid Serravallian (latest Badenian) when sediment input increased and coastal environments prograded seawards. The Badenian/Sarmatian boundary roughly coincided with a 400-kyr-eccentricity as well as with a 1.2-Myr obliquity minimum.
-
The Global Stratotype Section and Point (GSSP) of the Serravallian Stage (Middle Miocene)
Episodes, 2009Co-Authors: Frederik J Hilgen, Wout Krijgsman, Silvia Maria Iaccarino, Rodolfo Sprovieri, Hemmo A. Abels, Isabella Raffi, E. Turco, Willem-jan ZachariasseAbstract:The Global Stratotype Section and Point (GSSP) for the Base of the Serravallian Stage (Middle Miocene) is defined in the Ras il Pellegrin section located in the coastal cliffs along the Fomm Ir-Rih Bay on the west coast of Malta (35°54'50"N, 14°20'10"E). The GSSP is at the base of the Blue Clay Formation (i.e., top of the transitional bed of the uppermost Globigerina Limestone). This boundary between the Langhian and Serravallian stages coincides with the end of the major Mi-3b global cooling step in the oxygen isotopes and reflects a major increase in Antarctic ice volume, marking the end of the Middle Miocene climate transition and the Earth's transformation into an "Icehouse" climate state. The associated major glacio-eustatic sea-level drop corresponds with sequence boundary Ser1 of Hardenbol et al. (1998) and supposedly with the TB2.5 sequence boundary of Haq et al (1987). This event is slightly older than the last common and/or continuous occurrence of the calcareous nannofossil Sphenolithus heteromorphus, previously considered as guiding criterion for the boundary, and is projected to fall within the younger half of Chron C5ACn. The GSSP level is in full agreement with the definitions of the Langhian and Serravallian in their respective historical stratotype sections in northern Italy and has an astronomical age of 13.82 Ma.
-
integrated stratigraphy and astronomical tuning of the Serravallian and lower tortonian at monte dei corvi middle upper miocene northern italy
Palaeogeography Palaeoclimatology Palaeoecology, 2003Co-Authors: Frederik J Hilgen, Wout Krijgsman, Isabella Raffi, Abdul H Aziz, E. TurcoAbstract:An integrated stratigraphy (calcareous plankton biostratigraphy, magnetostratigraphy and cyclostratigraphy) is presented for the Serravallian and lower Tortonian part (Middle^Upper Miocene) of the Monte dei Corvi section located in northern Italy.The detailed biostratigraphic analysis showed that both the Discoaster kugleri acme and the first influx of Neogloboquadrina acostaensis are recorded at Monte dei Corvi; these events, which passed unobserved in previous studies, play an important role in delineating the Serravallian^Tortonian boundary.Thermal and alternating field demagnetization revealed a characteristic low-temperature component marked by dual polarities.The resultant magnetostratigraphy for the upper part of the section can be unambiguously calibrated to the GPTS ranging from C5n.2n up to C4r.2r. Unfortunately, the lower part of the section, including the Serravallian^Tortonian boundary interval, did not produce a reliable magnetostratigraphy despite the fact that some short reversed intervals and a single normal interval are recorded.Using sedimentary cycle patterns in combination with the calcareous plankton biostratigraphy the section can be correlated cyclostratigraphically in detail to the partially overlapping and previously tuned section of Monte Gibliscemi on Sicily.The Monte dei Corvi section is dated astronomically by calibrating the basic small-scale sedimentary cycles to the precession and 65‡N lat.summer insolation time series of the La93 solution following an initial tuning of larger-scale cycles to eccentricity.An almost perfect fit is found between the cycle patterns and intricate details, especially precession^obliquity interference, in the insolation target between 8.5 and 10 Ma. The tuning to precession remains robust for most intervals back to the base of the section dated at 13.4 Ma and shows that the section is continuous apart from a possible short hiatus in the Tortonian. It provides accurate astronomical ages for all sedimentary cycles, calcareous plankton events, polarity reversals and ash layers and marks a significant improvement of the recently proposed astronomical calibrations of the Monte dei Corvi section and of parallel sections in the Mediterranean.Astronomical ages for the Ancona and Respighi ashbeds are significantly older than previously reported 40 Ar/ 39 Ar biotite ages, even if the revised older age for the FCT-san dating standard of 28.02 Ma is applied. The astronomical dating of the magnetic reversals in the Monte dei Corvi section results in the completion of the astronomical polarity time scale for the last 13 Myr.The Monte dei Corvi section has recently been proposed as the stratotype section for the Serravallian^Tortonian boundary despite the moderate to
-
Integrated stratigraphy and astronomical tuning of the Serravallian and lower Tortonian at Monte dei Corvi (Middle–Upper Miocene, northern Italy)
Palaeogeography Palaeoclimatology Palaeoecology, 2003Co-Authors: Frederik J Hilgen, Wout Krijgsman, Isabella Raffi, H. Abdul Aziz, E. TurcoAbstract:An integrated stratigraphy (calcareous plankton biostratigraphy, magnetostratigraphy and cyclostratigraphy) is presented for the Serravallian and lower Tortonian part (Middle^Upper Miocene) of the Monte dei Corvi section located in northern Italy.The detailed biostratigraphic analysis showed that both the Discoaster kugleri acme and the first influx of Neogloboquadrina acostaensis are recorded at Monte dei Corvi; these events, which passed unobserved in previous studies, play an important role in delineating the Serravallian^Tortonian boundary.Thermal and alternating field demagnetization revealed a characteristic low-temperature component marked by dual polarities.The resultant magnetostratigraphy for the upper part of the section can be unambiguously calibrated to the GPTS ranging from C5n.2n up to C4r.2r. Unfortunately, the lower part of the section, including the Serravallian^Tortonian boundary interval, did not produce a reliable magnetostratigraphy despite the fact that some short reversed intervals and a single normal interval are recorded.Using sedimentary cycle patterns in combination with the calcareous plankton biostratigraphy the section can be correlated cyclostratigraphically in detail to the partially overlapping and previously tuned section of Monte Gibliscemi on Sicily.The Monte dei Corvi section is dated astronomically by calibrating the basic small-scale sedimentary cycles to the precession and 65‡N lat.summer insolation time series of the La93 solution following an initial tuning of larger-scale cycles to eccentricity.An almost perfect fit is found between the cycle patterns and intricate details, especially precession^obliquity interference, in the insolation target between 8.5 and 10 Ma. The tuning to precession remains robust for most intervals back to the base of the section dated at 13.4 Ma and shows that the section is continuous apart from a possible short hiatus in the Tortonian. It provides accurate astronomical ages for all sedimentary cycles, calcareous plankton events, polarity reversals and ash layers and marks a significant improvement of the recently proposed astronomical calibrations of the Monte dei Corvi section and of parallel sections in the Mediterranean.Astronomical ages for the Ancona and Respighi ashbeds are significantly older than previously reported 40 Ar/ 39 Ar biotite ages, even if the revised older age for the FCT-san dating standard of 28.02 Ma is applied. The astronomical dating of the magnetic reversals in the Monte dei Corvi section results in the completion of the astronomical polarity time scale for the last 13 Myr.The Monte dei Corvi section has recently been proposed as the stratotype section for the Serravallian^Tortonian boundary despite the moderate to
Damien Do Couto - One of the best experts on this subject based on the ideXlab platform.
-
Tectonic and stratigraphic evolution of the Western Alboran Sea Basin in the last 25 Myrs
Tectonophysics, 2016Co-Authors: Damien Do Couto, Christian Gorini, Laurent Jolivet, Noëmie Lebret, Romain Augier, Charles Gumiaux, Elia D 'acremont, Abdellah Ammar, Haddou Jabour, Jean-luc AuxietreAbstract:The Western Alboran Basin (WAB) formation has always been the subject of debate and considered either as a back-arc or a forearc basin. Stratigraphic analyses of high-resolution 2D seismic profiles mostly located offshore Morocco, enabled us to clarify the tectonic and stratigraphic history of the WAB. The thick pre-rift sequence located beneath the Miocene basin is interpreted as the topmost Malaguide/Ghomaride complex composing the Alboran domain. The structural position of this unit compared with the HP–LT exhumed Alpujarride/Sebtide metamorphic basement, leads us to link the Early Miocene subsidence of the basin with an extensional detachment. Above the Early Miocene, a thick Serravallian sequence marked by siliciclastic deposits is nearly devoid of extensional structures. Its overall landward to basinward onlap geometry indicates that the WAB has behaved as a sag basin during most of its evolution from the Serravallian to the late Tortonian. Tectonic reconstructions in map view and in cross section further suggest that the basin has always represented a strongly subsiding topographic low without internal deformation that migrated westward together with the retreating slab. We propose that the subsidence of the WAB was controlled by the pull of the dipping subducting lithosphere hence explaining the considerable thickness (10 km) of the mostly undeformed sedimentary infill.
-
Tectonic and stratigraphic evolution of the Western Alboran Sea Basin in the last 25 Myrs
Tectonophysics, 2016Co-Authors: Damien Do Couto, Christian Gorini, Laurent Jolivet, Noëmie Lebret, Romain Augier, Charles Gumiaux, Elia D 'acremont, Abdellah Ammar, Haddou Jabour, Jean-luc AuxietreAbstract:International audienceThe Western Alboran Basin (WAB) formation has always been the subject of debate and considered either as a back-arc or a forearc basin. Stratigraphic analyses of high-resolution 2D seismic profiles mostly located offshore Morocco, enabled us to clarify the tectonic and stratigraphic history of the WAB. The thick pre-rift sequence located beneath the Miocene basin is interpreted as the topmost Malaguide/Ghomaride complex composing the Alboran domain. The structural position of this unit compared with the HP–LT exhumed Alpujarride/Sebtide metamorphic basement, leads us to link the Early Miocene subsidence of the basin with an extensional detachment. Above the Early Miocene, a thick Serravallian sequence marked by siliciclastic deposits is nearly devoid of extensional structures. Its overall landward to basinward onlap geometry indicates that the WAB has behaved as a sag basin during most of its evolution from the Serravallian to the late Tortonian. Tectonic reconstructions in map view and in cross section further suggest that the basin has always represented a strongly subsiding topographic low without internal deformation that migrated westward together with the retreating slab. We propose that the subsidence of the WAB was controlled by the pull of the dipping subducting lithosphere hence explaining the considerable thickness (10 km) of the mostly undeformed sedimentary infill
